How to Replace Solar Light Batteries

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Going green for renewable energy is a great initiative, and every little bit of effort put towards that counts. One of them is the usage of solar lights, as they reduce the carbon footprint on this earth. Despite being very self-sufficient in most cases, solar lights rely heavily on their battery system in order for you to get the most out of it.

That being the case, over a couple of years of usage, your solar light batteries will start to get discharged and hence, needs replacement. That’s when the capacity of the batteries will start to go down, and the light output/duration of your solar light will also be reduced.

This article will explain further and educate you on how to replace solar light batteries.

Types of Solar Light Batteries

First of all, before jumping into how to replace these batteries, it’s important to recognize what type of battery the light uses. There are four types of rechargeable batteries that are used in solar lights, given below:

1. Lead Acid Batteries (AGM & Gel): 

ExpertPower 12v 7ah Rechargeable Sealed Lead Acid Battery

AGM and Gel type batteries are lead acid batteries. They both have the same chemistry and can only be charged with a smart charger. These batteries are generally sealed in a box, and they can only be replaced by the manufacturer.

2. Lithium-Ion Batteries: 

NERMAK 2 Pack 12V 10Ah Lithium Ion LiFePO4 Deep Cycle Battery, 2000+ Cycles Rechargeable Battery for Solar/Wind Power, UPS, Scooters, Lighting, Power Wheels, Fish Finder and More, Built-in 10A BMS

Lithium-ion batteries are more expensive than lead acid but last longer and have a better shelf life. However, these cells cannot be charged with any type of charger as it will damage their circuitry, so you have to get a special charger.

These batteries can be replaced by the same manufacturer or an authorized dealer.

3. NiMH Batteries: 

Tenergy Solla Rechargeable NiMH AA Battery, 1000mAh Solar Batteries for Solar Garden Lights, Anti-Leak, Outdoor Durability, 5+ Years Performance, 12 PCS, UL Certified

NiMH batteries are safe, environmentally friendly, and cost-effective, which makes them ideal for solar lights. These batteries are not affected by temperature, so they work fine in cold areas and hot places as well. 

4. NiCd Batteries: 

AA Ni-Cd 600mAh Yellow Rechargable Batteries for Solar Powered Units (4-Pack)

NiCd batteries are less efficient and have a shorter life cycle compared to other batteries. They are not safe for the environment as well because they contain highly toxic cadmium. The average life of these cells is around 5 years, with no maintenance required.

When it comes to replacing any of these types of batteries, it’s important to note that you should not mix different battery types. Always use the same type of battery in your solar lights, or else it will negatively affect the performance of your light.

Also Read: NiCad vs Lithium ion Batteries

how to replace solar light batteries

The following are the steps on how to replace a solar light battery: 

Step 1 – Identify What Kind of Solar Light Is It

There are multiple types of solar lights. It’s important to first identify what kind of solar light it is before you attempt to replace the battery. You can find this information on the manufacturer’s website or on the product label. This will allow you to purchase the correct replacement battery for your solar light.

Step 2 – Locate the Solar Rechargeable Batteries

Next, you’ll need to locate your solar rechargeable batteries. If you have a battery box with a clear plastic lid, then it’s easy to see where the battery is located. If not, then you’ll need to remove the light housing and check for any labels which will identify where the rechargeable batteries are located in your solar light.

Step 3 – Determine the Type of Battery

Once you locate the batteries, you’ll need to determine what type of battery your solar light uses. The manufacturer will have specific instructions on how best to replace the batteries in your solar lights. You can also use a multimeter to check the voltage since each battery type has a different voltage rating.

Step 4 – Order the Rechargeable Replacement Batteries

After that, you need to order the correct replacement batteries for your solar light. If you don’t know what type of solar light you use, then you might have to replace all of them at the same time. This is because it’s important not to mix different types of batteries in one solar device.

Step 5 – Replace the Batteries with Solar Lights

Finally, once you have the replacement batteries for your solar light, you can get started on replacing them. The positive and negative terminals of the new batteries will be clearly marked on the battery casing. However, if you are unsure, you can check in your owner’s manual for guidance.

Also Read: Exploring the Design and Benefits of Solar Batteries

Can I Replace Nickel Cadmium with Nickel Metal Hydride?

By ensuring the dimensions and voltage match, it is entirely conceivable to substitute nickel-cadmium batteries in solar lights with Nickel-metal Hydride (NiMH) ones. The foremost thing to keep in mind is that the two types of batteries must never be mixed.

To ensure optimal performance of your solar lights, use only one type of battery inside – either nickel-cadmium or nickel-metal hydride. Do not combine different types in a single light, as it will adversely affect the lighting’s functioning.

Can I Replace Nickel Cadmium with a Lithium-ion Battery?

There may be some cases where it is possible to replace nickel-cadmium with a lithium-ion battery in your solar lights with some modifications. However, this will depend on the specific type and model of the light, as well as the specific type of lithium-ion battery that you are using.

To be on the safe side, you should check with the manufacturer of your solar lights and the lithium-ion battery to determine if replacing these batteries is possible. If it is, you will need to carefully follow all instructions for replacing the batteries in your solar lights.

When To Replace Your Solar Light Batteries?

As rechargeable batteries are used and recharged, their total capacity starts to reduce after 100 battery cycles. Depending on the chemical construction of the battery, there is usually a 20% decrease in capacity at around 18 months.

If you’re looking to have your solar light stay lit for eight-ten hours nightly, it might be wise to consider a battery replacement every two years. By this means, you can amplify the likelihood that your solar light will remain shining gloriously in the night sky as intended.

How Long Do Solar Light Batteries Last?

For any typical solar light, the life of its rechargeable battery can range from two to ten years – depending on the type, capacity, and whether it is being used frequently. To make understanding this information simpler, we’ve created a helpful table for reference.

We have outlined the capacity range of 0-120 months to help you plan accordingly: 

100% Capacity 0 – 6 Months

90% Capacity 6 – 18 Months

80% Capacity 18 – 24 Months

70% Capacity 24 – 42 Months 

50% Capacity 60 – 120 months 

To ensure that your solar light batteries last as long as possible, it is important to keep them in a cool, dry area and avoid overcharging or over-discharging them. 


In conclusion, there are a variety of things to consider when replacing the batteries in solar lights, including the type and capacity of the battery, as well as any specific requirements or instructions provided by the manufacturer.

To ensure optimal performance of your solar light and to get the most out of your investment, it is generally recommended to replace the batteries in your solar lights every two years.

Additionally, it is important to carefully read all instructions and follow any pre-existing guidelines for replacing batteries in order to avoid further issues with your solar lights.

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